Re: [PATCH v5 01/18] xfs: compat_ioctl: use compat_ptr()

[Christoph Hellwig]

On Thu, Aug 15, 2019 at 07:37:53AM +1000, Dave Chinner wrote:
> > @@ -576,7 +576,7 @@ xfs_file_compat_ioctl(
> >  	case XFS_IOC_SCRUB_METADATA:
> >  	case XFS_IOC_BULKSTAT:
> >  	case XFS_IOC_INUMBERS:
> > -		return xfs_file_ioctl(filp, cmd, p);
> > +		return xfs_file_ioctl(filp, cmd, (unsigned long)arg);
> 
> I don't really like having to sprinkle special casts through the
> code because of this.

True.  But the proper fix is to not do the indirection through
xfs_file_ioctl but instead to call xfs_ioc_scrub_metadata,
xfs_ioc_bulkstat, etc directly which all take a void __user
arguments already.